Bus bar terminal means for pairs of circuit-braking elements

ABSTRACT

A readily removable terminal means, to make connection to two pairs of circuit breakers as used on an electric furnace, is provided without use of a terminal board and connectors therefrom. The terminal means consists of two U-shaped rigid bus bars each with a mounting flat and a supply wire connector lug mounted thereon. The outer U-shaped bus bar is sized so that its ends connect to the two outermost points of connection of the four aligned circuit breakers, while the ends of the inner Ushaped bus bar connects to the two innermost points of connection. Between its ends the inner bus bar is offset in a plane outwardly of the outer bus bar. This offset avoids any contact between it and the crossing supply wire to be connected to the inner bus bar.

United States Patent 11 1 Roth et al.

[4 1 Sept. 30, 1975 1 BUS BAR TERMINAL MEANS FOR PAIRS OF CIRCUIT-BRAKING ELEMENTS [751 Inventors: James E. Roth, Festus; Robert L.

Ol-learne, Kirkwood, both of Mo.

[73] Assignce: lntertherm, Inc., St. Louis, Mo.

[22] Filed: Aug. 6, 1974 [21] Appl. No: 495,225

3,152.287 10/1964 Edmunds 317/112 X FOREIGN PATENTS OR APPLlCATlONS 454,250 6/1968 Switzerland 317/119 Primary ExaminerRoy Lake Assistant E.\'aminerNeil Abrams [5 7 ABSTRACT A readily removable terminal means, to make connection to two pairs of circuit breakers as used on an electric furnace, is provided without use of a terminal board and connectors therefrom. The terminal means consists of two U-shaped rigid bus bars each with a mounting flat and a supply wire connector lug mounted thereon. The outer U-shaped bus bar is sized so that its ends connect to the two outermost points of connection of the four aligned circuit breakers, while the ends of the inner U-shaped bus bar connects to the two innermost points of connection. Between its ends the inner bus bar is offset in a plane outwardly of the outer bus bar. This offset avoids any contact between it and the crossing supply wire to be connected to the inner bus bar.

1 Claim, 1 Drawing Figure U.S. Patent Se t. 30,1975 3,909,097

BUS BAR'TERMINALMEANS FOR'PAI'RS' OF CIRCUlT-BRAKINGELEMENTS BACKGROUND OF,TH YE v1Ny i lriorsl Appliances such as electric furnacesaref normally equipped 'by the manufacturer with. twopairs-ofcircuit' breakers. To facilitate installationin amobilehome where only one power circuit is available,'a'singlecircuit terminal'board has been provided on the appliance,-with connectors to the'circuit breakers. Should the housing unit in-which' 'theappliance isto be in-z stalled haveprovisions for dividing the current, such terminal board'andit's connectors-willbe discarded; wasting'its costand the experlseoffits installation ?and' coniiec'tionsJIf after the furnace ileavges-the manufac- I turer it'is desired to re-conn'ect'such a terminal board; reconnection by anyone not an electrician experienced with the furnace may result inmixed connections with consequent damage." 1 H v s SUMMARY oF Tl-IE INvEnfrIQN 'The purposes of the present invention include providing' terminal means 'connectableto two pairs of circuit breakers, in substitution for such a terminal .board, which requires no physical attachment to the appliance or wirin'g to the circuit breakersg so that'it may be readily disconnected and'discarde'd'without undue experis'e for parts andlabor of installation. A further purpo'seis to provide terminal means which may,:after:disconnection, be readily reinstalled without danger of misconnection-flThe'se and other purposes lwill be apparent fromthe specification which follows.

The present invention is mounted'directly: onto the aligned points of connection of. the circuitbr'eakers. It consists-of novel rigid terminal means? made up of two substantially rigid U-shaped bus bar elements, each mounting-a supply wire connecting lu-gwTheouter of these U shaped bus bar-s has aspan equal tothe spacing of thetwo'outermostzpoints of connections tothe circuit breakers; while the inner bus bar has a span equal to thespacing of the two innermosppoints of connection. Betw'een their ends-the; bus bars extend in spacedapart planes offset from each other,- tomid-portions having mountingflats. Mounted on each flat, in electrical contact withit is a supply wireconnector Iug.-T he mid-portions of thebusbars', on which thelugs are mounted,'-are1so offset from each other as to position the connector lug on theninner bus bar inHa :plane spaced outward of the outer bus bar. This not only maintains electrical spacing between the bus bars but, more significantly, permits the supply wire to be connected to the inner bus bar connector to cross over the outer bus bar at a substantial spacing, sufficient to avoid contact between them.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a perspective view, partly from below, of bus bar terminal means embodying the present invention, installed on two pairs of conventional circuit breakers mounted on the cabinet of an electric furnace, as shown in phantom lines.

DESCRIPTION OF THE PREFERRED EMBODIMENT Electric furnaces, such as manufactured for installation in mobile homes and the like, have resistance heater elements to be supplied with current, usually upp encon'necti'On points d from which'current is led to the furnace heating elements, and lower points of connec'tioi'i generally designated e,' aligned along their lower edg esijthrough which current is to be supplied. The; lower points ofconne'c'tion e arepreferably of the type 'fhavingf'a 'horizontal fizlampfscrew acting in a contact-block f with a verticalentrant-opening. If, instead off'tliei'pres'ent' invent'i'o'n, a terminal board was usedfm'ountedon the "furnace cabinet, supply wires from it would be led upward into suchentrant openings of theco ri't act blocks f." l

'The present bus'b 'ar terminal means requires no attachmenftda furnace 'cabinet g or elsewhere other tdthiirciiit' breaker points of connection 'e. An outer U-s'haped' busbar generally designated 11 and an inher lil-sh'aped bus bargenerally designated 12 have no support other than the 'securement, in the screwslgh pedf bmae blocks ffbftheir vertically upward projecting tips 13:14 respectiij/el y, formed to adiameter which facilitates clamped securement therein. The bus barslli l'iare formed "of an electrically conductive 'stibstahtia lly metali's' o that when soclamped theyj will not, 'under'forcesto be encountered, bend substantially frorn the position illustrated; in this position the space around andib'etween them insulates themfrom each othen The' span of the outer bus bar'l 1 between its tips l 3 equals the spacingbet'ween the two outermost points ofco nnection es'of the outer circuit breaker air a; likewiset'he spari'betiw'ee'n the ups 14 of the inner bus bar 12 equals the'spacing between the points ofconnection e'of the inner circuit'breaker pair QBieneathtips 13, the outer b us bar 11 'is bent back horizontally step portions 15 which provide an offset, from the line of connector points forthe re,-

. maining lower portion 16 of the outer bus bar ll.

This remaining portion l6 lies, in a vertical. plane close to the rear surfaces of the circuit breaker s' afAs seen it is Ll-shaped and'preferably substantially semi circula r', which shape isreadily attained in production by bending, Atz and jadjacentto its lower midpoint has on its forward surface a mounting flat l7 pierced to provide a bore 18 for screw-mounting a conventional supply-wire connector lug 19 in electrical contact therewith.

The inner bus bar 12 is formed somewhat similarly but, except for its tips 14, its parts are of lesser length. Thus it has aft-formed step portions 25 which offset it aft from the connector points e only enough to provide adequate space for making a connection forwardly of it beneath the surface of the metal box which is to cover it. Below the step portions 25 its lower remaining portion 26 lies in a vertical plane which, as seen from the left of the drawing, is well forward of the parallel plane in which the portion 16 of the outer bus bar 11 is located. The planar portion 26 is likewise U-shaped and preferably nearly semi-circular. When viewed as from the right of the drawing, perpendicular to the spaced-apart parallel planes of the lower bus bar portions 16, 26, the inner bar 12 is throughout its length spaced inwardly of the outer bar 1 1. Thus an insulating air spacing is maintained.

As discussed, the plane of the U-shaped portion 26 of the inner bus bar 12 is forward of the corresponding portion 16 of the outer bus bar 11. At and adjacent to the lower midpoint of the U-shaped portion 26, its forward surface has a mounting flat 27, bored for screwmounting a second, inner connector lug 29 on its forward surface.

The rigidity of the bus bars ll, 12 provide firm unyielding support for the connector lugs 19, 29. When their tips l3, 14 are vertically mounted into and clamped on the connector points 0, connector lugs 19, 29 are supported as firmly as by a terminal board,

Noproblem exists in connecting tothe outer bus bar lug 19 a first heavy duty supply wire h. This is due in part to its spacing outwardly of the inner bus bar portion 26. However, connecting a second supply wire to supply current to the inner bus bar 12 presents the problem that while such supply wire must cross over the outer bus bar 11, it must not come into contact with it. This danger is eliminated by providing the spacing between the vertical planes of the portions 16, 26, achieved by the difference in the lengths of the step portions 15, 25. This difference in length offsets the inner lug 29 well forwardly of the plane of the outer lower bus bar portion 16.

The rigid U-shapes of bus bars ll, 12 provide easy, fool-proof attachment and removal. Even an unskilled worker knows immediately which tips l3, 14 to insert into which of the circuit breaker connector points (3. This is particularly important if the parts are disconnected and then reconnected by someone other than the manufacturer of the furnace or other appliance on which the circuit breaker pairs 0, b are installed. The danger of mis-connection which exists in the prior art is effectively eliminated.

Since the bus bars ll, 12 require no support structure and no connectors other than thetwo lugs 19, 29, a substantial saving is effected in initial cost of parts and installation, over the conventional terminal board, which usually has six lugs and four connectors therefrom.'Added to this saving is the saving of expense of disconnection of such a terminal board assembly if, on installation of thefurnace, dual circuitry is already available.

The present invention is useful for other appliances and in other environments where dual pairs of circuit breakers or fuses are mounted with their connector points in alignment. The references in this specification to outer and inner pairs of circuit'breakers are applicable to installations using two conventional two-pole circuit breakers whose left and right halves are each the circuit equivalent of a single pole circuit breaker. When mounted alongside each other their outer circuit breaker halves constitute the outer circuit breaker pair a and their inner halves the inner circuit breaker pair I). The term U-shaped" is intended to mean any shape, whether curved or squared, which includes a midportion establishing a span between connector tips or ends. Use of the term bus bar is not intended to preclude the use of insulation on portions between the tips l3, l4 and the mounting flats 17, 27. These and other variants in detail will be obvious, from this specific ation, to persons having ordinary familiarity with the subject matter. I

' We claim:

1. For use with two pairs of circuit-breaking elements having points of connection aligned in a plane,

terminal means comprising an outer substantially rigid bus bar whose span between its ends equals the spacing between the two outermost of such aligned points of connection,

an inner substantially rigid bus bar whose span between its ends equals the spacing between the two innermost of such aligned points of connection,

the ends of said bus bars being prong-like, whereby to facilitate securement to such points of connection,

the portions of both bus bars between their ends being U-shaped and proportioned according to their spans, whereby when viewed perpendicular to said U'-shaped portions, the inner bus bar is throughout its length spaced inwardly of the outer bus bar,

said proportioned portions being formed in parallel planes offset from the plane of said prong-like endswhen said ends are so aligned for connection, the plane of the inner bus bar portion being offset forwardly of the plane of the outer bus bar portion,

each said offset portion having a mounting flat, and

a supply wire connector lug mounted on each said flat in electrical contact therewith;

whereby to maintain electrical spacing between the bus bars and to avoid contact between the outer bus bar and a supply wire to be connected to the I lug on the inner bus bar.- 

1. For use with two pairs of circuit-breaking elements having points of connection aligned in a plane, terminal means comprising an outer substantially rigid bus bar whose span between its ends equals the spacing between the two outermost of such aligned points of connection, an inner substantially rigid bus bar whose span between its ends equals the spacing between the two innermost of such aligned points of connection, the ends of said bus bars being prong-like, Whereby to facilitate securement to such points of connection, the portions of both bus bars between their ends being U-shaped and proportioned according to their spans, whereby when viewed perpendicular to said U-shaped portions, the inner bus bar is throughout its length spaced inwardly of the outer bus bar, said proportioned portions being formed in parallel planes offset from the plane of said prong-like ends when said ends are so aligned for connection, the plane of the inner bus bar portion being offset forwardly of the plane of the outer bus bar portion, each said offset portion having a mounting flat, and a supply wire connector lug mounted on each said flat in electrical contact therewith; whereby to maintain electrical spacing between the bus bars and to avoid contact between the outer bus bar and a supply wire to be connected to the lug on the inner bus bar. 